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annfail10.hs:9:1: error:
Ambiguous type variable ‘a0’ arising from an annotation
prevents the constraint ‘(Data a0)’ from being solved.
Probable fix: use a type annotation to specify what ‘a0’ should be.
These potential instances exist:
instance (Data a, Data b) => Data (Either a b)
-- Defined in ‘Data.Data’
instance Data All -- Defined in ‘Data.Data’
instance (Data (f a), Data a, Typeable f) => Data (Alt f a)
-- Defined in ‘Data.Data’
...plus 39 others
(use -fprint-potential-instances to see them all)
In the annotation: {-# ANN f 1 #-}
annfail10.hs:9:11: error:
Ambiguous type variable ‘a0’ arising from the literal ‘1’
prevents the constraint ‘(Num a0)’ from being solved.
Probable fix: use a type annotation to specify what ‘a0’ should be.
These potential instances exist:
instance forall (k :: BOX) (f :: k -> *) (a :: k).
Num (f a) =>
Num (Alt f a)
-- Defined in ‘Data.Monoid’
instance Num a => Num (Product a) -- Defined in ‘Data.Monoid’
instance Num a => Num (Sum a) -- Defined in ‘Data.Monoid’
...plus 14 others
(use -fprint-potential-instances to see them all)
In the annotation: {-# ANN f 1 #-}
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